In production type of machining operations, magnetic faceplate chucking is infrequently used since time is lost and skilled operator attention is required for centering each workpiece on the faceplate. A dial indicator and skillfully dealt hammer blows to the workpiece are required to center the workpiece. Of course, the object for the operator is to center the workpiece on the faceplate with the geometrical axis of the workpiece substantially coaxial with the rotational axis of the faceplate that is attached on a rotatable spindle.
It is an object of the invention to provide a centering mechanism for centering a workpiece on a magnetic or other chuck and which eliminates the time consuming and labor intensive manual centering technique and is amenable for automatic control by a machine tool control unit.